The present invention is versatile. It has four signficant modes of use, that of an insulating wall or window, a thermal diode or valve, a heat storage panel and when the above modes of use are combined, a passive solar collector. In order to adequately present the background of the invention in a clear manner, each mode of use is discussed separately.
The efficiency of an insulator is affected by the amount of heat loss by conduction, convection, or radiation. It has been found that heat loss due to conduction and convection can be significantly reduced to near zero by evacuating the air within an enclosed space. Heat loss due to radiation can be inhibited by the use of surfaces that are of low emittance. Until now, the problem of evacuating an air space for the purposes of insulating has been difficult due to atmospheric pressure that is exerted upon the exterior surfaces. With at atmospheric pressure of about 14.7 lbs./sq. inch, an evacuated container will have an atmospheric pressure of approximately one ton per square foot. Not all materials are strong enough to withstand the atmospheric pressure on their own. In most cases there is a need to support the exterior of a structure that contains a vacuum. Additionally, different materials will expand and contract at different rates as the temperature rises and falls. If a container is constructed of two or more different types of material that are sealed together, and the materials expand and contract at different rates, then there is a great possibility that the seal will rupture causing a break in the vacuum. Not all materials are suitable to maintain a vacuum. For example, plastics are organic substances and are therefore permeable to gases. Eventually, any plastic or partially plastic container will lose the vacuum.
Currently, walls of houses 31/2 inches thick that are constructed using standard insulation material have an R value of 11. A building constructed of the present invention with walls 3 inches thick would have an insulation value as high as R 466, an improvement of 4,200%. Further, the 3 inch wall of the present invention could be designed structurally sufficient in itself to support the building, requiring no other support structure. Ordinary windows have an insulation value of approximately R 0.81 and double-pane windows have an insulation value of approximately R 1.4. A window constructed of the present invention would have an insulation value of over R 11, a 780% improvement.
On a smaller scale, the present invention can be constructed as a cabinet for use as a refrigerator or an oven. A conventional domestic refrigerator has approximately 1 inch of fiberglass insulation and has an R value of 4. A domestic refrigerator of the present invention would have walls approximately 1/4 inch thick and have an R value of 48, an improvement of 1,200% in insulation value and an improvement of 1,500% in space utilization. An appliance constructed of the present invention would require less energy to maintain a specified temperature. As a result, homes and industries would spend less money in energy costs for heating or cooling and would require smaller heating or cooling units.